The present invention relates to a method and apparatus for monitoring objects in flight and more particularly, the invention is directed to a method and apparatus for monitoring objects with high contrast as compared to a background and for monitoring such objects for a significant amount of the object""s flight. The present invention is also directed to a method and apparatus for monitoring objects in three-dimensions if desired.
Methods and apparatus for measuring flight characteristics of an object, such as a golf ball, are known. Some of these methods and apparatus are used to determine an angle, spin rate and speed of the ball at launch. Some of these apparatus use photodetectors to detect a golf ball position shortly after impact or launch and to trigger a flash that allows a camera to take a photograph. Such methods and apparatus are disclosed in U.S. Pat. No. 4,063,259. This data is typically referred to as the ball""s xe2x80x9claunch conditionsxe2x80x9d because this data accompanies the launch of the ball. Such data is collected over a short time significantly less than a second and a short distance significantly less than a yard.
The total travel distance of a golf ball includes its carry distance and its roll distance. The carry distance extends from where the ball leaves a tee or the ground to where it initially contacts the xe2x80x9cgroundxe2x80x9d after flight. The roll distance includes the distance from where the ball contacts the ground to where it comes to a complete stop after rolling or bouncing. The total travel distance can range from about 50 yards to about 300 yards depending on the shot. Prior art apparatus, such as that disclosed in the ""259 patent, only measure the golf ball""s launch conditions over less than a yard excluding the golf ball""s characteristics over a significant portion of the ball""s total travel distance. Such apparatus use launch condition data to predict total travel distance and ball trajectory.
Other patents disclose measuring the golf ball along other portions of the ball flight. U.S. Pat. No. 5,471,383 discloses measuring instantaneous velocity and spin but does not determine the ball""s characteristics over a significant amount of the total travel distance.
Furthermore, the golf ball""s flight has a horizontal component, a vertical component, and a depth component. Most prior art devices measure each component separately or the horizontal and vertical components together. U.S. Pat. No. 4,136,387 discloses taking images from three orientations but only for launch conditions, again excluding a significant amount of the total travel distance of the ball.
Additionally, conventional monitors are designed for use outdoors in daylight or in well-lit large rooms. When used outdoors in daylight, the ball flies across a background (i.e., sky) that may offer little contrast to the ball. In order to take useful images of the ball in flight in these conditions, some prior art monitoring devices are designed for use with golf balls having contrasting areas formed thereon. These areas can be about the size of some dimples. One drawback to using such a method is that the contrasting areas must be placed precisely on the ball, which can be time consuming. More importantly in order for cameras to see such areas to form images, light must be emitted along the camera""s line of sight and be reflected off of the areas back to the camera. Since the ball is fast moving and these reflecting areas are relatively small, it is difficult if not impossible to obtain such images over more than a short distance of less than about a yard.
Another device for use in daylight is disclosed in U.S. Pat. No. 5,342,051. The ""051 patent predicts where a ball would fly and a single camera tracks the predicted flight and purportedly captures the ball image. If the ball does not follow the predicted path, the necessary data may not be obtained.
Therefore, a need exists for a method and apparatus for monitoring preferably a significant amount of the total travel distance of a golf ball, particularly outdoors, that offers high-contrast, does not require placing small contrasting areas on the ball, and that, if desired, can measure horizontal, vertical and depth components of the ball""s flight.
The present invention is directed to method of monitoring an object in flight. This method includes providing at least a portion of an outer surface of the object with a phosphorescent material and exciting the phosphorescent material so that the phosphorescent material emits light. The method further includes the steps of providing at least one camera, launching the object in flight, transmitting the light toward the at least one camera so that the at least one camera captures at least one image of the object in flight, and determining data for the object in flight using the at least one image of the object. More preferably, between at least two and ten images are taken by each camera.
The present invention is also directed to a method of monitoring an object in flight that includes providing an object in a stationary position and providing at least two cameras. One of the cameras is positioned downstream of the object in the stationary position and the other is positioned upstream of the object in the stationary position. The method further includes launching the object from the stationary position into flight, capturing images of the object in flight at least until the object passes through an apex in flight using the cameras, and determining data for the object in flight using the images of the object.
Furthermore, the present invention is directed to a combination of an apparatus and an object that comprises at least one light-emitting object and at least one non-light emitting camera. The camera receives a light emitted from the object in a predetermined range of wavelengths and processes the light to produce at least one image of the object in motion.
The present invention is also directed to an apparatus for monitoring an object in flight that comprises at least one movable camera, at least one stationary camera, and at least two filters located to receive a light emitted from the object before transmission to the associated camera. The filters allow the light to enter the associated camera and the cameras capture at least one image of the object in flight.
The present invention may also be an apparatus for monitoring an object in flight that comprises at least one first camera, a second camera, at least one first filter, and a second filter. The first camera includes a first line of sight substantially perpendicular to a flight path of the object so that the first camera captures images of the ball along a substantial length of the flight path. The second camera includes a second line of sight angularly offset from the flight path of
the object by less than about 90 degrees. Each first filter is associated with each first camera and located to receive a light emitted from the object before transmission to the associated first camera. The first filter allows the light to enter the associated first camera and allows the at least one first camera to capture at least one image of the object in flight. The second filter is located to receive a light emitted from the object before transmission to the second camera. The second filter allowing the light to enter the second camera and allows the second camera to capture at least one image of the object in flight.
The above methods and apparatus can be used to take images of the ball for over about 6 seconds of ball flight and over about 200 yards of flight distance and do not require the cameras to have a light thereon for emitting light toward the ball during ball imaging.